(a) Field
The present disclosure relates to an automatic transmission for a vehicle. More particularly, the present disclosure relates to a planetary gear train of an automatic transmission for a vehicle that improves power delivery performance and fuel economy by achieving ten forward speed stages with a minimum number of constituent elements being used and improves silent driving of the vehicle by using operation point positioned at a low engine speed.
(b) Description of Related Art
Generally, an automatic transmission achieving more speed stages has been developed to enhancing fuel economy and optimizing drivability. Recently, increase of oil price is triggering a hard competition in enhancing fuel consumption of a vehicle.
Therefore, many researches for reducing weight and enhancing fuel economy through downsizing of an engine and for securing drivability and fuel economy through multiple speed stages of automatic transmissions have been developed.
However, in the automatic transmission, as the number of speed stages increase, the number of internal components (particularly, planetary gear sets) increase, and as a result, a length of the transmission increases. Therefore, mountability, cost, weight, transmission efficiency, and the like may still deteriorate.
Accordingly, development of a planetary gear train which may achieve maximum efficiency with a small number of components may be important in order to increase a fuel economy enhancement effect through the multiple-speeds.
The above information disclosed in this Background section is only for enhancement of understanding of background of the invention. Applicant notes that this section may contain information available before this application. However, by providing this section, Applicant does not admit that any information contained in this section constitutes prior art.